With the development of touch display techniques, there is a variety of touch functions and operation manners in the display product. At present, in addition to the conventional touch function, a force touch function is also achieved by providing a force sensing unit in the display product. The force sensing unit is generally a four-end device, including two input ends and two output ends. In the prior art, a display panel includes multiple force sensing units, input ends of the force sensing units are connected with a force detection circuit. During force touch, a bias voltage input circuit provides a bias voltage to the force sensing units, when a user presses the display panel, the panel will deform, so that the voltage value output by the force sensing unit changes, and the force detection circuit judges the magnitude of the press of the user according to the voltage value output by the force sensing unit.
However, since each connecting line is considered as a resistor, which may be load with a voltage, but the total voltage is limited. As a result, sensitivity of the force sensing unit will be low due to the fact that the voltage value output by the force sensing unit is in positive correlation with the bias voltage value, the smaller the bias voltage value, the lower the sensitivity of the force sensing unit.